Mercurial > dropbear

comparison libtomcrypt/src/pk/pkcs1/pkcs_1_mgf1.c @ 293:9d110777f345 contrib-blacklist

Find changesets by keywords (author, files, the commit message), revision number or hash, or revset expression.
propagate from branch 'au.asn.ucc.matt.dropbear' (head 7ad1775ed65e75dbece27fe6b65bf1a234db386a) to branch 'au.asn.ucc.matt.dropbear.contrib.blacklist' (head 1d86a4f0a401cc68c2670d821a2f6366c37af143)
author Matt Johnston <matt@ucc.asn.au>
date Fri, 10 Mar 2006 06:31:29 +0000
parents 1b9e69c058d2
children 0cbe8f6dbf9e
comparison
equal deleted inserted replaced
247:c07de41b53d7 293:9d110777f345
1 /* LibTomCrypt, modular cryptographic library -- Tom St Denis
2 *
3 * LibTomCrypt is a library that provides various cryptographic
4 * algorithms in a highly modular and flexible manner.
5 *
6 * The library is free for all purposes without any express
7 * guarantee it works.
8 *
9 * Tom St Denis, [email protected], http://libtomcrypt.org
10 */
11 #include "tomcrypt.h"
12
13 /**
14 @file pkcs_1_mgf1.c
15 The Mask Generation Function (MGF1) for PKCS #1, Tom St Denis
16 */
17
18 #ifdef PKCS_1
19
20 /**
21 Perform PKCS #1 MGF1 (internal)
22 @param seed The seed for MGF1
23 @param seedlen The length of the seed
24 @param hash_idx The index of the hash desired
25 @param mask [out] The destination
26 @param masklen The length of the mask desired
27 @return CRYPT_OK if successful
28 */
29 int pkcs_1_mgf1(const unsigned char *seed, unsigned long seedlen,
30 int hash_idx,
31 unsigned char *mask, unsigned long masklen)
32 {
33 unsigned long hLen, x;
34 ulong32 counter;
35 int err;
36 hash_state *md;
37 unsigned char *buf;
38
39 LTC_ARGCHK(seed != NULL);
40 LTC_ARGCHK(mask != NULL);
41
42 /* ensure valid hash */
43 if ((err = hash_is_valid(hash_idx)) != CRYPT_OK) {
44 return err;
45 }
46
47 /* get hash output size */
48 hLen = hash_descriptor[hash_idx].hashsize;
49
50 /* allocate memory */
51 md = XMALLOC(sizeof(hash_state));
52 buf = XMALLOC(hLen);
53 if (md == NULL || buf == NULL) {
54 if (md != NULL) {
55 XFREE(md);
56 }
57 if (buf != NULL) {
58 XFREE(buf);
59 }
60 return CRYPT_MEM;
61 }
62
63 /* start counter */
64 counter = 0;
65
66 while (masklen > 0) {
67 /* handle counter */
68 STORE32H(counter, buf);
69 ++counter;
70
71 /* get hash of seed || counter */
72 if ((err = hash_descriptor[hash_idx].init(md)) != CRYPT_OK) {
73 goto LBL_ERR;
74 }
75 if ((err = hash_descriptor[hash_idx].process(md, seed, seedlen)) != CRYPT_OK) {
76 goto LBL_ERR;
77 }
78 if ((err = hash_descriptor[hash_idx].process(md, buf, 4)) != CRYPT_OK) {
79 goto LBL_ERR;
80 }
81 if ((err = hash_descriptor[hash_idx].done(md, buf)) != CRYPT_OK) {
82 goto LBL_ERR;
83 }
84
85 /* store it */
86 for (x = 0; x < hLen && masklen > 0; x++, masklen--) {
87 *mask++ = buf[x];
88 }
89 }
90
91 err = CRYPT_OK;
92 LBL_ERR:
93 #ifdef LTC_CLEAN_STACK
94 zeromem(buf, hLen);
95 zeromem(md, sizeof(hash_state));
96 #endif
97
98 XFREE(buf);
99 XFREE(md);
100
101 return err;
102 }
103
104 #endif /* PKCS_1 */
105
106 /* $Source: /cvs/libtom/libtomcrypt/src/pk/pkcs1/pkcs_1_mgf1.c,v $ */
107 /* $Revision: 1.4 $ */
108 /* $Date: 2005/05/05 14:35:59 $ */